1. Field of the Invention
The present invention relates to indexing systems for rotary orienters. Rotary orienters position articles being conveyed on a conveyor system so that a feature of each article is facing in the same predetermined direction, for example, with a handle leading. The invention is directed to an improved apparatus for indexing the rotation of articles, rotating them rapidly but smoothly to a precise predetermined orientation about their vertical axis. The apparatus may be used in conjunction with filling, capping, labeling and inspection of containers, or other similar operations.
2. Description of the Prior Art
The packaging industry handles many different articles that must be packaged, filled, processed, or acted on in some manner. These articles are made in many different sizes and shapes that are not necessarily symmetrical. They may have a handle, an opening, or another feature that is off center, or they may have other identifiable characteristics. In the packaging industry, the articles may require that a label be applied to a particular side, or that a product be inserted through an opening in the article, or some other requirement that necessitates the articles being oriented in a uniform manner while being processed along a production line. The articles may be introduced to a linear conveyor system with these key features randomly oriented, for example the off-center opening into a container. It is then necessary to index the opening of the articles to be filled so that the opening of each article will be aligned with a filling spout. The indexing system is critical to ensure the selected feature of the articles are rotated to the same precise orientation, so the next apparatus in the production line may operate on each article with the same result. Light weight containers require stabilization during rotation to prevent them from falling over or being ejected from the container orienter. A gripper, platform or other apparatus is frequently used to engage the top of the container to prevent tipping. While the grippers and platforms rotate freely there is still a resistance in this apparatus. During high-speed rotation, this resistance causes a gripped container top to rotate more slowly than the container bottom while bringing the container bottom up to rotation speed, causing fragile light weight containers to twist and become permanently distorted. To avoid this problem, the gripper, platform or other apparatus must be driven at the precise start time and at the precise speed at which the support for the bottom of the container is rotating.
Apparatus for orienting articles that use various indexing methods, are well-known in the packaging industry. The patent to Schneemann, U.S. Pat. No. 4,606,244, illustrates a complex apparatus for incrementally rotating a turntable from one workstation to another. This apparatus is actuated by a linearly translating driver. The primary purpose of the apparatus is to firmly lock the turntable with a locking pawl at each workstation The apparatus does not permit selective rotation and is overly complex for use in orienting articles.
U.S. Pat. No. 3,934,714, issued to Takao Matsumoto, uses a friction wheel attached to the rotatable table that selectively engages a centrally driven friction wheel for rotation of the table. A detection device issues a signal to the indexing system to initiate rotation. A terminating signal frees the friction wheel of the rotatable table from the central friction wheel. An electromagnetic brake is used to stop the rotation of the rotatable table in response to the terminating signal. The use of friction wheels and electromagnetic brakes provide a system that is imprecise.
U.S. Pat. No. 3,957,154 discloses yet another method for rotation of containers, however this rotation is for inspection or labeling purposes of round containers and precise positioning is unnecessary.
Notwithstanding the existence of such prior art indexing systems, it remains clear that there is a need for a rotary orienter having an indexing system that will permit smooth and precise rotation of a fragile article. The apparatus gripping the top of the container and the apparatus gripping the bottom of the container must both be driven simultaneously to rotate the container to a predetermined position to enable further production steps to be precisely undertaken.